1. Technical Field
The invention relates generally to circuit control mechanisms and more particularly, but not exclusively, to techniques for assigning identifiers to components accessed via a control interface.
2. Background Art
Various radio frequency front-end (RFFE) interface standards and system power management interface (SPMI) standards released by the MIPI® Alliance are some examples of mechanisms that provide for unique slave identifiers (USIDs) to variously address different respective components of a platform. Typically, such components are coupled to a configuration and/or control (“configuration/control” herein) bus, where host logic, also coupled to the configuration/control bus, functions as a master to control the components.
During a power up or reset of a conventional platform, such slave components are each associated with a default identifier that is defined by the component's vendor, manufacturer or the like. USIDs are then variously assigned to facilitate addressing of the components, where such addressing does not use the components' default identifiers. One reason for this is to account for the possibility that two components from the same manufacturer (or vendor, etc.) have the same default identifier.
In the particular case of MIPI® RFFE standards and MIPI® SPMI standards, USIDs are defined as values of some fixed (limited) size—e.g., four-bit values, where one such four-bit value (such as 0b0000) is reserved as a broadcast identifier. This limits to fifteen (15) the total number of available USID to be used according to various MIPI®-compliant control interfaces. Therefore, for a given use case, a system implementing MIPI®-compliant control mechanisms is limited to no more than fifteen slave components that can be addressed by the same control bus during that use case.
A system can mitigate the effects of limited USID availability by implementing one or more additional configuration/control buses. However, the use of multiple configuration/control buses increases system complexity and cost, and decreases the efficiency of resource utilization. One additional configuration/control bus can require at least three additional contacts on a bus master device. Furthermore, the bus-master must adopt multiple bus identifiers as an additional addressing element. As the variety and complexity of use cases for mobile devices continue to grow, there is an increasing demand for efficient mechanisms to accommodate such use cases.